Seeking a More Flattering Light on, and From, Bulbs

Saturday

Dr. Robert Pai is optimistic about the fluorescent industry’s chances of developing light bulbs that please everyone and meet the efficiency standards that Congress has mandated for 2012.

SOME 26 years ago, when Robert Pai joined Sylvania’s fluorescent technology laboratories, he and his fellow researchers did not think much about compact fluorescents. They were more interested in solving problems with mercury and ballast, and otherwise making big industrial fluorescent lamps more efficient and safer for the environment. Much has happened since. Sylvania is now part of Osram Sylvania, a unit of the German company Siemens. Dr. Pai — he has a doctorate in physics — is heading compact fluorescent research. And compact fluorescents, usually called C.F.L.’s, are definitely on researchers’ minds.

In a recent conversation, Dr. Pai, who is retiring this month, explained why some of the problems with compact fluorescents — they do not work with dimmer switches, they still use mercury and they make people and objects look weird — remain intractable. But he expressed optimism about the industry’s chances of developing light bulbs that please environmentalists, energy conservationists and finicky consumers in time to meet the efficiency standards that Congress has mandated for 2012. Excerpts from the interview follow:

Q. Despite all the hoopla surrounding them, compact fluorescents are still not big sellers. Isn’t it time to pursue light-emitting diodes, or some other answer to light bulb efficiency?

A. We’re all looking at L.E.D.’s and other technologies. But we really are making progress with C.F.L.’s, too. We’ve got programs to address the problem with dimmers. We’ve been testing a new bulb that looks promising in terms of consumer acceptance for the quality of the light. But I admit, people who are extremely color-conscious will have to wait another few years before they can happily leave incandescents.

Q. The common perception is that people who are even mildly color-conscious must avoid compact fluorescents. Why is that?

A. The fact that you’re even asking the question means this industry has not done a good job of advertising the strides we’ve made in quality of light.

Q. What about quality, period? Compact fluorescents are supposed to last much longer than incandescents, but I’ve heard lots of complaints from people whose C.F.L.’s burned out quickly.

A. All of the big manufacturers make their bulbs in China, and we do, too. But we have Sylvania people there whose full-time job is to ensure that vendors are maintaining product quality. We are confident that our 10,000-hour lamp will last 10,000 hours. The problem, though, is that anybody can import C.F.L.’s from China, which means there’s an awful lot of unbranded and untested product in the stores.

Q. Can you explain in layman’s terms why you cannot eliminate mercury and ballast from compact fluorescents, and why they shed harsh light?

A. Generating light is a function of vapor pressure. Too little vapor, and most of the energy goes to heat the lamp. Too much vapor, and the light gets trapped and degenerates into heat. Mercury is still the only substance that yields just enough vapor pressure to shed light efficiently without having to heat the lamp.

Ballast, which is what converts electrical power into a form that can be used by the lamp, poses a different problem. We’ve had experimental lamps that could operate with electricity that comes directly from the wall outlet. But when the current or the temperature deviated even slightly, the lamp exploded.

And as for the light — think of a blacksmith heating up a horseshoe. First it glows red, then orange, then as it gets hotter, it glows blue and white. Compact fluorescents do get hot, particularly in enclosed fixtures, and that’s why they shed that bluish-white light. We need to find ways to add more red to the spectrum.

Q. What are the relative pluses and minuses of the different kinds of light sources?

A. Incandescents are still the simplest technology. You throw some electricity into a filament and it lights up. And they offer full-spectrum color. But about 95 percent of the energy is wasted as heat, and making them more efficient would also make them much more expensive. Halogen lamps, common for automotive headlights or spotlights in retail displays, are a bit more efficient, but they’re also more expensive.

C.F.L.’s are extremely efficient, and cheaper to operate over their lifetime. But the color just isn’t the same as incandescents, they don’t work well for spot lighting and for now they don’t work with dimmer switches.

Most of the research is aimed at L.E.D.’s. They generate many colors of light and they are very efficient. But for now, they have big downsides, too. It is expensive to dissipate their heat, and they become less efficient if you diffuse the light over a wide area.

Q. Are any of those problems close to being solved?

A. I don’t expect much change in the immediate future. But I’ll bet that anything I say now will be out of date 5 or 10 years down the road.

Q. I understand you are retiring to Florida. How will you light your new home?

A. The place we’re moving to has all kinds of dimmers, so I’m going to have to negotiate with my wife about taking some of them out. But I guess I won’t be using C.F.L.’s in places like the dining room until the dimmer problem is solved. And I figure, eventually we’ll all convert to L.E.D.’s. But my crystal ball is not good enough to say when.

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